1. Field of the Invention
This invention relates generally to functionalized rubber and more specifically, to methods for functionalizing rubber elastomers and products made therefrom.
2. Description of the Related Art
The tire industry in recent years has been investing in research to improve the fuel economy of vehicles by reducing the rolling resistance of tires. One of the results of that research was to provide functionalized rubber products that when incorporated into the tire compositions used for making tire components does in fact reduce the rolling resistance of tires and thereby improve the fuel economy of trucks and cars.
In some rubber compositions useful for making tire components, it is known to use all or just a portion of such functionalized rubber for the manufacture of the tire components, the remainder of the rubber being non-functionalized.
Functionalized rubbers are known to be those that are appended with active moieties and they are well known in the rubber industry. The functionalization of the rubber may occur at the backbone of the elastomer and/or at the branch ends by attaching these active moieties to the polymer.
One example of a functionalized elastomer may be found in U.S. Pat. No. 6,013,718 that discloses a diene polymer that has been functionalized with a silanol functional group or a polysiloxane block having a single silanol end.
U.S. Pat. No. 6,503,973 discloses a functionalized elastomer that has been functionalized with a carboxylic acid function at one or at each of its chain ends.
U.S. Pat. No. 7,786,208 discloses functionalizing natural rubber latex by graft polymerization as an emulsion polymerization process.
While it is known that functionalized elastomers are useful in the rubber and tire industries, new methods of providing functionalized elastomers and new functionalized elastomers are still being sought to improve the physical characteristics of the rubber and to improve the performance of tires.